GDI Floating-Point Services

Kernel-mode graphics drivers must do all floating-point operations between calls to the GDI-supplied EngSaveFloatingPointState and EngRestoreFloatingPointState routines.

If the hardware has a floating-point processor, the driver can do floating-point operations directly. Otherwise, the driver can use the GDI FLOATOBJ services shown in the following table to emulate floating-point operations. Regardless of processor type, the driver should use the FLOATL data type when declaring floating-point values.

Function	Description
EngRestoreFloatingPointState	Restores the Windows 2000 and later kernel floating-point state after the driver uses any floating-point or MMX hardware instructions.
EngSaveFloatingPointState	Saves the current Windows 2000 and later kernel floating-point state.
FLOATOBJ_Add	Adds two FLOATOBJs.
FLOATOBJ_AddFloat	Adds a FLOATOBJ and a FLOATL.
FLOATOBJ_AddLong	Adds a FLOATOBJ and a LONG.
FLOATOBJ_Div	Divides one FLOATOBJ by another.
FLOATOBJ_DivFloat	Divides a FLOATOBJ by a FLOATL.
FLOATOBJ_DivLong	Divides a FLOATOBJ by a LONG.
FLOATOBJ_Equal	Determines whether two FLOATOBJs are equal.
FLOATOBJ_EqualLong	Determines whether a FLOATOBJ and a LONG are equal.
FLOATOBJ_GetFloat	Calculate and return the FLOAT-equivalent value of a FLOATOBJ.
FLOATOBJ_GetLong	Calculate and return the LONG-equivalent value of a FLOATOBJ.
FLOATOBJ_GreaterThan	Determines whether one FLOATOBJ is larger than another.
FLOATOBJ_GreaterThanLong	Determines whether a FLOATOBJ is larger than a LONG.
FLOATOBJ_LessThan	Determines whether one FLOATOBJ is less than another.
FLOATOBJ_LessThanLong	Determines whether a FLOATOBJ is less than a LONG.
FLOATOBJ_Mul	Multiplies two FLOATOBJ values.
FLOATOBJ_MulFloat	Multiplies a FLOATOBJ by a FLOATL.
FLOATOBJ_MulLong	Multiplies a FLOATOBJ by a LONG.
FLOATOBJ_Neg	Changes the sign of a FLOATOBJ.
FLOATOBJ_SetFloat	Sets a FLOATOBJ to a particular FLOATL value.
FLOATOBJ_SetLong	Sets a FLOATOBJ to a particular LONG value.
FLOATOBJ_Sub	Subtracts one FLOATOBJ from another.
FLOATOBJ_SubFloat	Subtracts a FLOATL from a FLOATOBJ.
FLOATOBJ_SubLong	Subtracts a LONG from a FLOATOBJ.